Circular Economy Applied to Sludge Minimization: The STAR Project

Area of Science:

• Environmental Engineering
• Biotechnology
• Wastewater Treatment

Background:

• Biological sludge management from wastewater treatment plants (WWTPs) faces challenges from increasing production and emerging pollutants.
• Efficient sludge reduction and resource recovery are critical for sustainable wastewater management.

Purpose of the Study:

• To investigate the integration of a thermophilic aerobic membrane reactor (TAMR) for biological sludge minimization.
• To assess resource recovery potential and compatibility with conventional activated sludge (CAS) systems.

Main Methods:

• A six-month industrial-scale monitoring of a TAMR system in a medium-size WWTP.
• Evaluation of volatile solids (VSs) reduction in thickened sludge.
• Assessment of TAMR residue compatibility with CAS systems through respirometric tests.

Main Results:

• The TAMR unit achieved up to a 90% reduction in volatile solids (VSs).
• The STAR configuration (TAMR + CAS) reduced sludge output to 10% of conventional levels.
• TAMR residues proved biologically treatable and suitable for reuse as carbon sources, enhancing CAS performance.

Conclusions:

• Integrating mesophilic and thermophilic systems (like TAMR and CAS) significantly improves sludge management efficiency.
• This approach lowers operating costs and reduces environmental impacts associated with wastewater treatment.
• Enhanced resource recovery and improved system performance are key benefits of the STAR configuration.